Spectroscopic evidence for SN 2010ma associated with GRB 101219B

TL;DR

This paper presents spectroscopic evidence linking supernova SN 2010ma to the gamma-ray burst GRB 101219B at redshift 0.55, demonstrating that supernova signatures can be observed at large distances and strengthening the GRB-SN connection.

Contribution

First spectroscopic detection of a supernova associated with a GRB at z=0.55, confirming the GRB-SN link at cosmological distances with detailed spectral analysis.

Findings

Supernova signatures observed 16.4 and 36.7 days after the burst.

GRB 101219B has high gamma-ray energy and follows the Amati relation.

Spectroscopic SN features resemble those of SN 1998bw.

Abstract

We report on the spectroscopic detection of supernova SN 2010ma associated with the long gamma-ray burst GRB 101219B. We observed the optical counterpart of the GRB on three nights with the X-shooter spectrograph at the VLT. From weak absorption lines, we measure a redshift of z = 0.55. The first epoch UV--near-infrared afterglow spectrum, taken 11.6 hr after the burst, is well fit by a power law consistent with the slope of the X-ray spectrum. The second and third epoch spectra (obtained 16.4 and 36.7 days after the burst), however, display clear bumps closely resembling those of the broad-lined type-Ic SN 1998bw if placed at z=0.55. Apart from demonstrating that spectroscopic SN signatures can be observed for GRBs at these large distances, our discovery makes a step forward in establishing a general connection between GRBs and SNe. In fact, unlike most previous unambiguous GRB-associated SNe, GRB 101219B has a large gamma-ray energy (E_iso = 4.2 x 10^{51} erg), a bright afterglow, and obeys the "Amati" relation, thus being fully consistent with the cosmological population of GRBs.